Possible world models were introduced by Saul Kripke in the early 1960s. Basically, a possible worlds model is nothing but a graph with labelled nodes and labelled edges. Such graphs provide semantics for various modal logics: logics of necessity and possibility (alethic logics), logics of time (temporal logics), logics of knowledge and belief (epistemic... more...

Aristotle?s modal syllogistic is his study of patterns of reasoning about necessity and possibility. This volume provides a simple interpretation of Aristotle?s modal syllogistic using standard predicate logic, making it accessible to a wide range of readers. more...

Modal logics, originally conceived in philosophy, have recently found many applications in computer science, artificial intelligence, the foundations of mathematics, linguistics and other disciplines. Celebrated for their good computational behaviour, modal logics are used as effective formalisms for talking about time, space, knowledge, beliefs, actions,... more...

``Platonism and intuitionism are rival philosophies of Mathematics, the former holding that the subject matter of mathematics consists of abstract objects whose existence is independent of the mathematician, the latter that the subject matter consists of mental construction... both views are implicitly opposed to materialistic accounts of mathematics... more...